Table 1.

Studies reporting on associations between SES and structural brain development.

	Study	Participants	SES measures	Areas of the brain	Morphometry analysis	Main findings
Children	Eckert et al., 2001	10–12 years old	Participation in a federally subsidized school lunch program.	Whole-brain and ROIsa in planum temporale and central sulcus	MRI: cerebral volume (PV-wave and manual tracing); surface areas of ROIs (manual tracing)	Children who participated and children who did not participate in a federally subsidized school lunch program showed similar correlations between planum temporale asymmetry and phonological skill, although phonological skill was lower in the lower-SES group.
		M = 11.4 years	Low-income families had annual incomes less than $14,597
		N = 39
	Hanson et al., 2013	0–5 years old	Family income	Whole-brain and ROIs in frontal, parietal, temporal, and occipital lobes	MRI: cerebral volume; gray and white matter volumes in ROIs (Expectation–Maximization algorithm)	Children from lower income families had lower total gray matter volumes, and frontal and parietal volumes. No differences were found for total cerebral volume or parietal and temporal lobes. Children from lower income families showed reduced total gray matter trajectory.
		M = 13.5 months (first scan)	Mode = $50k to $75k
			Range = $0 to > $100k
		N = 77	SES categories
			Low-SES (= or < 200% of FPL), Moderate-SES (between 200 and 400% of FPL), High-SES (greater than 400% of FPL)
	Jednoróg et al., 2012	8–10 years old	Hollingshead 2-factor index	Whole-brain and ROIs in hippocampi, middle temporal gyri, left fusiform, right and inferior occipito-temporal gyri. Overall white matter microstructure	MRI: VBMb—total brain volume and gray matter volumes in ROIs (SPM8); SBMc—intracranial volume, hemispheric thickness, total surface area, and gray matter surface area, thickness, and volumes in ROIs (FreeSurfer) DTId: Fractional anisotropy (BrainVISA and FSL)	Hollingshead Index positively correlated with gray matter volumes in hippocampi, parahippocampal, gyri, middle temporal gyri, insula, left fusiform gyrus, right inferior occipito-temporal region, and left superior/middle frontal gyrus. Hollingshead values not significantly correlated with white matter microstructure.
		M = 9.6 years	(maternal education and maternal occupation)
		N = 23
			Mean = 44, SD = 28
			Range = 84–11
			(Low- to high-SES families)
	Luby et al., 2013	6–12 years old	Family Income-to-Needs (ITN)e	Whole-brain and ROIs in hippocampus and amygdala	MRI: cerebral volume; gray and white matter volumes in ROIs (FreeSurfer)	Family ITN positively correlated with total white and gray matter volumes as well as hippocampal and amygdala volumes. Effects of poverty on hippocampal volume were mediated by caregiving and stressful life events, but not parental education.
		M = 9.8 years	Mean = 2.14, SD = 1.27
		N = 145	Range = 0–4.74
			Parental education
			Mode = Some college (38%)
			Range = Less than HS to graduate degree
	Raizada et al., 2008	5-year-olds	Hollingshead 4-factor index	Left inferior frontal gyrus	MRI: gray and white matter volume in ROI (SPM5)	Hollingshead Index was marginally positively correlated with both gray and white matter volumes in the left inferior frontal gyrus.
		M = 5.3 years	(Marital status, employment, educational attainment, and occupational prestige)
		N = 14
			Range = 31.5–66
			(Middle- to high-SES families)
Children and Adolescents	Hanson et al., 2011	4–18 years old	Family income	Whole-brain and ROIs in hippocampi and amygdalae	MRI: VBM- total brain volume and gray matter volumes in ROIs (DARTEL and SPM8)	Family income was positively correlated with hippocampal volume. No association between income and amygdala volumes. Positive correlation between paternal ED, but not maternal ED, and total and right hippocampal volumes. No relationship between income and cerebral volume.
		M = 11.2 years	Range = Less than $5k—more than $100k
		N = 317
			Mode = $75k–$100k (28%)
			Parental education
			Range = Less than HS to graduate degree
			Mode = College (27%)
	Lange et al., 2010	4–18 years old	Family income	Whole-brain and ROIs in intracranial cavity, cerebellum, brainstem, thalamus, caudate nucleus, putamen, globus pallidus, and frontal, temporal, parietal, and occipital lobes	MRI: total brain volume (sum of gray and white matter volumes in ROIs plus cerebrospinal fluid); gray and white matter volumes in ROIs (automated tissue segmentation algorithm)	Parental education levels were not correlated with brain volumes. Both family income and parental education were related to full scale IQ. Positive correlation between full scale IQ and cerebral volume. Total or regional brain volumes do not mediate association between parental education and IQ in children.
		M = 10.9 years	Mean = 73, 047, SD = 1816
		N = 285	Less than $50K (27%), $50k–$100k (50%), greater than $100k (23%)
			Parental education
			Range = HS to graduate degree
			Mean = 73, 047, SD = 1816
			Modes = College (31%) and Graduate School (31%)
	Brain Development Cooperative Group, 2012	4–18 years old	Family income	Whole-brain and ROIs in intracranial cavity, cerebellum, brainstem, thalamus, caudate nucleus, putamen, globus pallidus, and frontal, temporal, parietal, and occipital lobes	MRI: total brain volume (sum of gray and white matter volumes in ROIs plus cerebrospinal fluid); gray and white matter volumes in ROIs (“mni_autoreg” software package and automatic nonlinear image matching and anatomical labeling)	Family income and parental education levels were not associated with any regional brain volume.
		M = 10.9 years	Mean = 72, 458, SD = 31,695
		N = 325	Parental education
			Modes = College (31%) and graduate school (31%)
			Range = HS to graduate degree
	Lawson et al., 2013	4–18 years old	Family income	Frontal gyri (superior, middle and inferior), anterior cingulate gyri, and orbitofrontal gyri	MRI: cortical thickness (ANTS and DiReCT)	Parental education, but not family income, predicted increased cortical thickness in the left superior frontal gyrus and right anterior cingulate gyrus. No parental education by age interactions.
		M = 11.5 years	Mode = $75k–$100k (27%)
		N = 283	Range = Less than $5k–$150k
			Parental education
			Mean = 7.53, SD = 2.31
			Range = 2–12
	Noble et al., 2012a	5–17 years old	Income-to-Needs (ITN)	Left temporal gyrus (superior, middle, and inferior), left fusiform gyrus, hippocampi, amygdalae, and anterior cingulate cortex	MRI: gray and white matter volumes in ROIs (FreeSurfer)	Parental education was negatively correlated with amygdala volume. No correlation between ITN and amygdala volume. ITN was positively correlated with hippocampal volume, but no correlation between parental education and hippocampal volume. Education by age interaction observed in left superior temporal gyrus and left inferior frontal gyrus.
		M = 11.4 years	Mean = 3.3, SD = 1.9
		N = 60	Range = 0.23–6.7
			Parental education
			Mean = 15.1, SD = 2.7
			Range = 8–21 years
Adults	Butterworth et al., 2012	44–48 years old	Experience of financial hardship over past year	Amygdala and hippocampus	MRI: gray and white matter volumes in ROIs (FreeSurfer)	Experience of current financial hardship was correlated with smaller hippocampus and amygdala. Childhood poverty was not associated with either brain structure.
		M = 46.7 years
		N = 403	4 dichotomous variables: pawned or sold something, went without meals, unable to heat home, or asked for help from welfare/community organizations
			Childhood poverty (y/n)
	Cavanagh et al., 2013	36–65 years old	Early life SES (ESES)	Cerebellum	MRI: cerebellar gray matter volume (FreeSurfer)	Both early life and current SES predicted cerebellar gray matter volume. Current SES explained significant additional variance to early life SES, but not vice-versa. Lower SES was associated with smaller cerebellar gray matter volumes.
		M = 50.94 years	(Number of siblings, people per room, paternal social class, parental housing tenure, and use of a car by family)
		N = 42
			Current SES (CSES)
			(Current income, current social class, current housing tenure)
	Chiang et al., 2011	18–29 years old	Adult occupation (Australian socioeconomic index: SEI)	Overall white matter microstructure	DTI: fractional anisotropy (FSL)	No main effect of SEI on white matter microstructure, but interaction between SEI and genetic components that affect white matter integrity. Higher SEI participants had higher heritability in the thalamus, left middle temporal gyrus, and callosal splenium. Lower SEI participants had higher heritability in the anterior corona radiate.
		M = 23.7 years
		N = 499	Median = 67.5
			25th Percentile = 39.7
			75th Percentile = 83.8
	Gianaros et al., 2007	31–54 years old	Subjective social status (SSS)	Anterior cingulate cortex, amygdala and hippocampus	MRI: VBM—total brain volume and gray matter volumes in ROIs (SPM2 and Matlab)	Lower subjective social status was associated with reduced gray matter volume in the perigenual area of the anterior cingulate cortex, but not anterior cingulate cortex, hippocampus, or amygdala. No associations between brain structures and educational attainment, income, personal, or community SES measures.
		M = 44.7 years	Education
		N = 100	Mode: College (47%)
			Range = Less than HS to PhD
			Income
			Mode: $50–65k (25%) and greater than $80k (25%)
			Personal SES = composite of education and income
			Community SES = zip code
	Gianaros et al., 2012	30–50 years old	Educational attainment	Overall white matter microstructure	DTI: fractional anisotropy (FSL)	Individuals higher in education, earning higher incomes, and living in more advantaged communities demonstrated increases in white matter integrity and decreases in radial diffusivity.
		M = 40.7 years	M = 17.17, SD = 3.2
		N = 155	Range = 11–24 years
			Income Community SES
	Krishnadas et al., 2013	35–64 years old	Neighborhood SES	Overall brain network structure and cortical thickness	MRI: cortical thickness (FreeSurfer)	Controlling for age and alcohol use, compared to the least deprived (LD) group the most deprived (MD) had significant cortical thinning in bilateral perisylvian cortices.
		M = 51 years	Scottish index of multiple deprivation (SIMD)
		N = 42
	Liu et al., 2012	67–79 years old	Education	Temporal pole, transverse temporal gyrus, and isthmus of cingulate cortex	MRI: volumes in 15 ROIs and cortical thickness in 33 ROIs (FreeSurfer)	Participants with higher levels of education had significantly larger temporal pole, transverse temporal gyrus, and isthmus of cingulate cortex.
		M = 73 years	M = 11 years, SD = 2.5
		N = 113	Range = 6–16 years
	Noble et al., 2012b	17–87 years old	Educational attainment	Amygdala and hippocampus	MRI: amygdala and hippocampal volumes (FreeSurfer)	Education by age interaction found in the hippocampus, such that the volumetric reduction seen at older ages was more pronounced among less educated individuals, and was buffered among more highly educated individuals. No main effects of education or age by education interactions found for amygdala volumes.
		M = 39.7 years	High school or less (32%)
		N = 275	Some college (30%)
			College and graduate degree (38%)
	Noble et al., 2013	17–23 years old	Educational attainment	White matter microstructure (ROIs: superior longitudinal fasciculus, cingulum bundle, anterior coronal radiata)	DTI: fractional anisotropy (fMRIB Diffusion Toolbox and FNIRT)	Educational attainment significantly correlated with white matter microstructure in the superior longitudinal fasciculus and cingulum bundle (controlling for age).
		M = 20.1 years	Mean = 14.1, SD = 1.8
		N = 47	Range = 11–18 years
	Piras et al., 2011	18–65 years old	Educational attainment	Thalamus, caudate nucleus, putamen, globus palidus, hippocampus, and amygdala	MRI: Gray and white matter volumes in ROIs DTI: fractional anisotropy and mean diffusivity (FSL)	Educational attainment negatively correlated with microstructural changes in both left and right hippocampi (controlling for age).
		M = 40.35 years	M = 14.5, SD = 3.3
		N = 150	Range = 5–21 years
	Staff et al., 2012	Older adults	Educational attainment	Hippocampus	MRI: hippocampal volume (FreeSurfer)	Childhood SES (latent factor including paternal occupation and childhood home environment) positively correlated with hippocampal volume after adjusting for mental ability (at age 11), adult SES (self-occupation and current neighborhood environment) and educational attainment.
		M = 68.7 years	Paternal occupation
		N = 235	Retrospective at age 11
			Self-occupation
			Range = 1–9
			Current neighborhood environment
			Zip code
			Childhood home environment
			Number of public rooms in home and number of people expected to share sanitation facility

^aROI, region of interest.

^bVBM, voxel-based morphometry.

^cSBM, surface-based morphometry.

^dDTI: diffusion tensor imaging.

^eIncome to Needs (ITN), total family income divided by the federal poverty level for a family of that size, in the year data was collected.